Welding machine



Aug. 22', 1944. H. A. ALLSHOUSE ETAL WELDING MACHINE 5 Sheets-Sheet 1Filed Dec.

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mv Harry /7 ATTORNEY Aug. 22, 19 H. A. ALLSHOUSE ET AL 2,356,543

WELDING MACHINE Filed Dec. 15, 1941 5 Sheets-$heet 2 INVE TOR5 f/arryfl. l/s/Iouse: 0, /iex H. Dye/r ATTORNEY i i a Aug. 22, 1944.

H. A. ALLSHOUSE EI'AL WELDING MACHINE Filed Dec. 15, 1941 5 Sheets-Sheet3 usem/v 1944- H, A. ALLSHOUSE ETAL ,3 6, 43

WELDING MACHiNE 5 Sheets-Sheet 4 Filed Dec. 15, 1941 ATTORNEY T944- H.A. ALLSHOUSE ETAL 2,356,643

WELDING MACHINE 7) Filed Dec. 15, 1941 s 'ShetsShee 5 lNVENT s Harlfl zz lmusem ATTORNEY Patented Aug. 22, 1944 UNITED STATES PATENT OFFICEClaims.

This invention relates to electric welding machines, particularly thosefor welding continuous seams, and has for its principal object toprovide a machine of this character wherein the work to be welded isrigidly supported in welding position on the machine and the electrodesare movable along the seam together with a percussion means which actson the work directly in the path of the welding current passed betweenthe electrodes.

Other objects of the invention are to provide a machine of thischaracter which is of simple design and substantially semi-automatic inoperation; and to provide a machine capable of welding metals of variousthickness and particularly metals of light gage.

In accomplishing these and other objects of the invention, ashereinafter pointed out, we have provided improved structure, thepreferred form of which is illustrated in the accompanying drawings,wherein:

Fig. 1 is a side elevational view of a welding machine constructed inaccordance with the present invention, the work being welded and a partof the work supporting table being shown in sec- Fig. 6 is a similarview but showing the switches in circuit breaking position.

Fig. 7 is an enlarged section through the elec trode carriageparticularly illustrating the percussion means for smoothing andlevelling the seam.

Fig.8 is a fragmentary perspective View of the percussion means.

Fig. 9 is an enlarged view of the hammer head of the percussion means.

Figs. 10 to 12 inclusive are diagrammatic views showing formation ofa'weld.

Fig. 13 is a fragmentary side elevational view IS on the respectivesides of the web I5.

of the end brackets. ""and 23 project through the bearings 24 and carry[designates a welding machine constructedin accordance with the presentinvention andwhich includes a base'2having a flat, table-like top 3supported upon legs l. Mounted on'the top 3,

' at the respective endsthereof, are brackets 5 and G'eachhavinglegs 1'and 8 provided with'feet 9 that are secured'to the top 3 by fasteningdevices, such as bolts). The upper ends of the legs are connectedbycross-bars l l carrying pairs of vertical posts or guides l2 and I3.

Slidably mounted on the posts 12 and I 3, for movement to and from thetable top 3 is a beam ortr-ack member M which, in'the'illustratedinstance, is of H formation and has its web portion l5 arrangedvertically and extending longitudinally of the machine with the upperand lower flanges l6 and I! positioned horizontally to form upper andlower wheel engaging surfaces [8 and The ends of the beam or'trackmember are movably supported on cams 20 and 2| that are fixed totransverse shafts 22 and 23 mounted in pairs of bearings 24 and-25carried on the cross-bars H The ends of the shafts 22 hand-wheel 33 ismanipulated to rotate the shaft the forms 28 and 29 rotate the wormgears and 21 to rotate the shafts 22 and 23 for swinging the earns 20and 2! into raising and lowering position relatively to the beam ortrack member, the peripheries of the cams engaging the under face of thelower flange l1. Thus the beam may beraised and lowered on the pairs ofguide posts 12 and I3 to raise and lower a welding carriage 34, now tobe described.

The welding carriage illustrated in the present drawings includes ahorizontal platform havingplate-like legs 36 and 31 depending over thesides of the beam [4 to carry pairs of wheels or rollers 38 engaging thetrack surface i9 of the lowermost flanges I1 and an intermediate upperwheel or roller 39 engaging the track surface l8 of theuppermost flangesIt as best shown in Figs. 1 and 3. The platform 34 is thus supported formovement longitudinally of the beam or track membenthe rollers beingsuitably journalled on the respective plate-like legs 36 and 31 asindicated at 43.

Carried on the platform 34 is a transformer 4!. The transformer 4|includes a primary winding 42 and a secondary 43, the secondary 43consisting of a plurality of laminations 44 bent to provide a horizontalbar portion 45 extending across the transformer and depending legportions 46 and 41 arranged alongside of the'legs 38 and 31 butinsulated therefrom by suitable insulation as indicated at 48, Fig. 3.The leg portions 46 are of sufiicient length to extend below the legs 36and 31 for mounting electrode supporting arms 49 and 50, the arms beingfixed to the legs 46 and 4'! of the secondary by fastening devices suchas cap-screws I which extend through suitable openings in thelaminations and into threaded sockets at the upper ends of the arms. Thelower ends 52 of the arms converge inwardly toward the top of the tableand have openings 53 mounting the shanks 54 of spindle members 55, thespindle members having disklike heads 55. Journalled on the spindlemembers are wheel-type electrodes 51 and 58 respectively, havingbevelled peripheral faces 59 and 60 arranged to engage the work carriedon the table top 3 and to roll smoothly thereover as the weldingcarriage 34 is carried along the beam. The disk-like heads of thespindle members are engaged in recesses 6| of the electrodes to retainthe electrodes for rotation about fixed axes. With this arrangement thelower portions of the disks or wheels are in position to engage themarginal portions of a seam to be welded while the upper portions arespaced apart to accommodate a percussion device 62 therebetween, laterdescribed.

In order to cool the electrodes, the spindle members 55 are preferablyprovided with passageways 63 having connection with flexible conduits 64and 65 which circulate a cooling medium to carry away thev heataccumulating in the electrodes.

The lower edges of the plate-like legs 35 and 3! terminate in inwardlyextending flanges 66 and SI extending under the lower flanges II of thetrack member I4 for supporting the percussion device 62. In theillustrated instance the percussion device comprises a pneumatic hammer68 having an air cylinder 69 thereof mounted on a plate I9 which isfixed to the flanges 66 and 8'1 by fastening devices II, as best shownin Fig. 3. The percussion device includes a reciprocat-ing shank I2slidable in the cylinder '69 and provided with a foot I3 which is bestillustrated in Figs. 8 and 9. The foot 13 has a flat sole l4 (see Figs.7, 8 and 9) adapted to engage the work, and upwardly rounding ends I5and I6 that are provided with groove portions TI and I8 for working downa flange formed on one of the members to be welded as the hammer movesthereover. The percussion means is supplied with an actuating medium,such as compressed air, through a hose 19, having connection with acontrol valve 80 which is connected by a pipe 8I with a suitable sourceof supply. The valve 80 is operated by a solenoid 82 which is connectedwith the electric control circuits, as later described.

The carriage is moved along the track member by means of a screw-shalt83 extending longitudinally of the track and having threaded engagementwith an arm 84 extending inwardly from the leg 3'! of the carriage. Theends of the shaft are Journalled in bearing brackets 85 and 86 fixed tothe ends of the web I5 as best shown in Fig. l. The end of thescrew-shaft adjacent the hand-wheel 33 is provided with a hand-wheel 81by which the shaft may be manually rotated. The opposite end of theshaft carries a gear wheel 88 that is adapted to be connected with theshaft by means of a clutch collar 89 engageable with a clutch face 90 onthe gear.

Mounted on the upper flange of the beam member, adjacent the endcarrying the gear 88, is a reversible motor SI having a pinion 92 on thearmature shaft 93 thereof meshing with the gear wheel 33 so that thescrew-shaft may be rotated in either direction under power of the motorwhenever the clutch collar 89 is engaged with the clutch face of thegear wheel 88.

Inlaid in the table top 3, directly under the line of the weld, is aninsert 94 formed of a metal which prevents sticking of the work to thetable top.

In welding flat sheets, and particularly those of light gage, we find itdesirable to clamp the sheets in welding position on the table top. Thisis effected by longitudinal bars 95 and 96 extending longitudinallyacross the top of the table and spaced apart a suiflcient distance toallow passage of the electrode wheels. The ends of the bars are carriedon piston rods 91 and 98 reciprocable through openings 99 in the tabletop 3 and having heads IOIl connected with the ends of the bars by wristpins IGI. Suspended below the table top are cylinders I02 carryingpistons I03 fixed to the ends of the respective piston rods. The lowerheads of the cylinders are closed by plates I04 and the upper ends byplates I05 which are provided with stufling boxes I06 to seal about thepiston rods. A fluid pressure medium is admitted to the respective endsof the cylinders by pipes I01 and I08 having common connections througha four-way valve I89 which is supplied with pressure medium through apipe III] and which is allowed to exhaust through a pipe I I I. When thevalve is set to admit pressure medium to the pipes I 08, pressure fluidis admitted to the lower end of the cylinders I 52 and raises thepistons I03 and lifts the clamping bars 95 and 96 from engagement withthe work. When the valve IDS is set in its other position. the pressuremedium is allowed to exhaust through the pipes I 08 and pressure mediumis applied to the upper ends of the cylinders through the pipes ID! tobring the clamping bars into engagement with the work.

In order to control movement of the welding carriage when the electrodesmove off of the work, the web I5 of the beam or track member I4 carrieslongitudinal rods H2 and H3 on the respective sides thereof. The rod H3is slidable in bearing brackets I I4 fixed to the beam I4 near therespective ends thereof and extends through a yoke-like notch I I 5 ofan arm I I6 depending inwardly from the leg 36 of the carriage, as bestshown in Fig. 3. Adjustably fixed on the rod, at the limits of movementof the carriage. are collars III and I I8 which are adapted to beengaged by the arm I I5 to effect shifting of the red when the armengages the respective collars. Fixed on one end of the rod is a collarH9 which engages the trip I20 of a toggle switch IZI so that when therod is shifted in one direction, as when the arm on the carriage engagesthe collar I I I, the switch arm is moved in one direction to open themotor circuit when the motor is rotated in one direction. and when therod is moved in the opposite direction, as when the arm of the carriageengages the collar I I8, the trip of the switch I 2| is moved in theopposite direction to stoppthe'motor 9| and :establish' ra vv connectionto reverse-rotation thereof upon clo-.=

sure-of a starting switch I22.

The welding current. is controlled byithe' rod.

II2. One end of this rodis slidable in'abearing I23 projecting from theweb I of'the track mem her-I4 and its opposite end-is connected by apinI24 with the central joint of toggle links I25 ano I26. ThelowertogglelinkIZByismounted onia pin-l21-fiXed to the-web-:ofthetrackmembei and the-outer endnoftheupperlinkil25 is connee-ted withaonearm 701'? a bell-crank lever I 28- through-apin I29.

The otherarm' \I 30 of the w bell-crank'lever carries a'contact -I3Iadapted'to a engage-a contact I32on an arm I33 which is-piv- 1 otal-lymounted on a pin-l34 carried by ,"the Web I5 of thetrack member -I4.'The arm. I3IJ'is so arranged that when. the toggle-links are in deadcenter position. as shown in "Fig. ,5, the contacts I3I and I32 areengaged sothat a-Welding circuit is-established to the electrode wheels51' and 58'.

When the toggle is swung to eitherside of dead center position, thebell-crank lever is actuated to-openthe circuit. This is efiected'bylimit col-.

lars I35'and I35 substantially registering with the collars I I1 and II8 on the rod" I I3 previously described, and adapted to be engaged byanotched 1 end:lI3'I of the bracket arm 84. The'rod II2 is' normallyretained inposition to close circuit by i springs. I38 and I39 sleevedon the rod and hav ingtone of .their ends engaging the bearing I23andtheir opposite ends engaging collars I40 and 1 moving the "togglelinks I25 and I26 to circuit breaking position; When the carriage movesaway fromthe collar I35inthe direction of the collar name spring. I39operates to shift the rod totheright' (Fig. 5) which rocks thebell-crank inan:antic1ockwise direction to close the circuit. When thearm84 of the carriage reaches the col lar -I36 the rod is shifted'again,this time, breaking the toggle to the right, compressing the spring I38and moving the toggle in aclockwise direction to openthe circuit. Whenthe move ment of the carriage is reversed. th'espring I38 againshiftsthe rod, this time to the left,to move the" toggle levers to dead centerposition, again closing the welding circuit.

The circuits connecting the respective mechanisms are best shown inFigs. 5 and 6. Current is supplied through service conductors I42 andI43 to the primary winding through branch conductors I44 and I45, theconductor I45 being I connected with thebell-crank lever I28 by-a branchconduct-or I45-and the other contact I32 is connected with the conductorI43 through a conductor I41 cooperating with-the branch I46 to'form acontinuation of the conductor M5.

the solenoid 82 andcircuit is completedthrough the solenoid to theconductor I42 by a conductor I49;

Current is also supplied from the conductors I42 and I43 to the switchI22 by means of con-- ductors I59 and I5I. The starting switch I22 isconnected with the switch I2! through con ductors I52, I53 and I54and-the switch I2I is connected with the motor 9i through conductors I55and I56. The switches I2I and -I22are-ofa switch.

In .welding sheets together; the marginal: edger "=of'one sheet a isprovided with a laterallyturned flangebagainst whichthe matingeclge c ofthe adjacent sheet-d abuts. In-applying the sheets to the table top 3,the valve I09 is adjusted so as to admit'pressure medium below thepistons and T exhaust pressure medium above the pistons,

thereby lifting the clamping bars and 96 from the table. The sheets aand d are then'slid unde'r the clamping bars with the edge 0 and flangeb thereof in abutting contact, as shown in Fig-'10,

and with the flange b arranged directly under l the path of the hammer68. The clamping bars 95 and '96 are then brought into clampingengagement with the marginal edges of the sheets aand i d by changingsetting of thevalve I09 so that 1 the pressure medium is exhausted fromthe lower ends'of the" cylinders I32 and admitted to the upper ends ofthe cylinders. Whenin non-weld-i in'g position'the carriage is at oneor'the other ends of the table with theelectrode wheels 51 and 58 out ofcontact with the sheets to be welded. Foreexample, assuming that thecarriage is in the position'shown in Fig. 1, the arm II'li'h'asv engagedthe collar I I8 and the switch I20-is open between the'closed positionof the switch I22" and the motor 9|, howevenwhen the switch I22 is swungto its other position, circuit isclosed to the motor 9I so that themotor begins to re tate the screw-shaft 83 in proper direction to beginfeed of the welding carriage toward the However, before" the electrodewheels 51 and 58 contact the sheets bppositeend of the machine.

a and d'the hand-wheel 33 is rotated to lower the electrode wheels intocontact with the work. As soon as the arm 84 on the carriage has movedaway from the collar l35'the spring I 38comes into play to shift the rodI I2 and allow the toggle links I25 and I26 to move'to switchclosing po'Currentthen fiows'to the primary 42 off the transformer -4I and to thesolenoid Valve 80. I A secondary or welding current is then generatedsition.

flange 2) and the hammer works on the upturned 1 flange to effectcompaction of the weld, as shown in Figyll; After the face of the hammermoves along-the flange, the flat portioncomes into contact therewith toreduce the thickness of the seam to the thickness of the metal sheets asshown in Fig.- 12. The Weld is made progressively across the width ofthe sheets until the electrode wheels move offthe opposite side when thearms 2 84 andII I6 engage the collars Ill and -I35,'shifting the rods 3'and H2 so that the motor cir: i cult is broken at the switch I2I and theto le links are moved to switch opening position, there'- byinterrupting flow of current to the primary winding of the transformerand to the solenoid, suspending the welding current in the secondary andflow of pressure medium to the percussion means. The position of thevalve I09 is then changed so that the pressure above the pistons isexhausted'and pressure medium. is admitted to the'lower'sides of thepistons for raising the" clamping bars from engagement with the sheets.

type :sothat current to the :motor. 9| fmay be es-i tablishedor brokenby manipulation of eithert:

The current The hand-wheel 33 is manipulated to cause raising of theelectrode wheels and prevent their engagement with the table. Themachine is then ready for making another weld in the same manner asabove pointed out, with the exception that when the switch I22 is movedto its original position, circuit is established to reverse the motor 9|so that the shaft is rotated in the opposite direction to feed thecarriage in reverse direction across the sheets to be welded.

The modified form of the invention shown in Figs. 13 and 14 issubstantially the same as that in the first form with the exception thatthe track member I 63 has fixed support from the table-like top I6I byend members I62. The Welding head including the transformer I63 issuspended from a carriage I64 that is movable along the track I60similar to the carriage previously described. In this arrangement thetransformer operates below the track and carries electrode wheels IE andI 56 which are rotatably supported on arms I61 and I68 pivotally mountedon the depending ends I69 and I10 of the secondar of the transformer bypins l'll a indicated in Fig. 13, The arms I61 and I58 are spaced apartto accommodate the hammer I12 that is adjustably supported from theframe of the transformer, as indicated at I13. The electrode wheels areretained in firm contact with the work to be welded by fluid pressureintroduced into cylinders I14 and I 15 and in which are mounted pistonsI15 having rods I11 pivotally connected with ears I18 on the arms I61and IE8. The upper ends of the cylinders are pivotally connected withsimilar ears I19 depending from the frame of the transformer. Acompressible fluid such as air is introduced to the respective ends ofthe cylinders to act on the respective sides of the pistons throughpipes I80 and I8I, the air being selectively admitted through therespective pipes un der control of a suitable valve (not shown). Thework is retained in position on the table in the same manner as in thefirst form of the invention and the transformer carriage is operated bya similar mechanism to move the electrode wheels across the work andeffect a Weld. When the wheels are to be moved into contact with thework, air is admitted to the cylinders I14 and I15 to act against theupper faces of the pistons to retain the wheels in yielding contact withthe work so that they may move over any irregularities and maintainconstant electrical contact therewith. To raise the Wheels after theyhave travelled across the work, air is shut off to the upper ends of thecylinders and is admitted to the lower ends of the cylinders to act onthe under face of the pistons to lift the Wheels from the work. Ifdesired, the metal at the point of the weld may be preheated or keptwithin a nonoxidizable zone by means of gas discharged from a nozzle I82which is carried by the welding head in front of the electrode wheels(Fig. 13).

From the foregoing it is obvious that we have provided a welding machinewhich is semi-automatic in operation and capable of performing a weldwherein the metal of the weld is reduced to the surface of the materialbeing welded.

What we claim and desire to secure by Letters Patentis:

1. A welding machine including, a work support, clamping means arrangedto clamp work to be welded on the support, a welding mechanism, acarriage supporting the welding mechanism, means supporting the carriagefor movement of the Welding mechanism across the work support, pneumaticpercussion means supported for movement with the welding mechanism,means for controlling flow of current to the welding mechanism, meansfor controlling an air suppl to said percussion means, and meansconnected with each of said control means and located in the path of apart movable with the carriage to actuate each of said control means.

2. A welding machine including, a work support, clamping means arrangedto clamp work to be welded on the support, a Welding mechanism, acarriage supporting the welding mechanism for movement across the worksupport, percussion means supported by said carriage and arranged tosmooth the weld effected by said Welding mechanism, a motor forreciprocating the carriage across the work support, and means forenergizing the motor including means for effecting actuation of thepercussion means.

3. A welding machine including, a work support, clamping means arrangedto clamp work to be welded on the support, a welding mechanism, acarriage supporting the welding mechanism for movement across the worksupport, percussion means supported by said carriage and arranged tosmooth the weld effected by said welding mechanism, a motor forreciprocating the carriage across the work support, means for energizingthe motor including means for efiecting actuation of the percussionmeans, and control means havin engagement with the carriage at selectedpositions of said carriage for stopping the motor including saidpercussion means.

4. A welding machine including, a work support, a pair of laterallyspaced clamping members coextensive with a seam to be welded and havingarrangement to clamp the work against the work support on the respectivesides of the seam to be welded, pressure actuated means carried by thesupport for moving said clamping members into and out of clampingposition, a track member carried above the work support in parallelrelation with the clamping members, a carriage mounted for movementalong the track member, electrodes on the carriage arranged to engagethe work at points intermediate said clamping members and on therespective sides of the seam, percussion means on the carriage andoperable on the seam backed by said work support to smooth the Weldefiected by said electrodes, means for moving the carriage along thetrack member, and means for rendering said moving means eii'ectiveincluding said percussion means.

5. A welding machine including, a work support, a pair of laterallyspaced clamping members arranged to engage the work on the respectivesides of a weld to be effected, cylinders carried by the support,pistons slidable in the cylinders, means connecting the pistons with theclamping members, means supplying a pressure fluid to said cylinders formoving said clamping members into and out of clamping position, a

track member carried above the work support, a carriage mounted formovement along the track member, electrodes on the carriage arranged toengage the work, percussion means on the carriage and operable 0n thework intermediate said electrodes, and means for moving the carriagealong the track member.

6. A welding machine including, a work supmeans carried byv the supportfor moving said clamping members into and out of clamping position, atrack member carried above the work support, a carriage mounted formovement along the track member, electrodes on the carriage arranged toengage the work, percussion means on the carriage and operable on thework intermediate said electrodes, means for moving the carriage alongthe track member, means for rendering said moving means effectiveincluding said percussion means, means supplying a welding current tothe electrodes, a switch controlling said current supply, and means foropening said switch at selected predetermined limits of movement of thecarriage,

'7. A Welding machine including, a work support, a pair of laterallyspaced clamping members arranged to engage the work on the respectivesides of a weld to be effected, means carried by the support for movingsaid clamping members into and out of clamping position, a track membercarried above the clamping members, a carriage mounted for movementalong the track member, electrodes on the carriage arranged to engagethe work, percussion means on the carriage and operable n the workintermediate said electrodes, means for moving the carriage along thetrack member, means for rendering said moving means effective includingsaid percussion means, means supplying a welding current to theelectrodes, 3, switch controlling said current supply, and means foropening said switch at selected predetermined limits of movement of thecarriage.

8. A welding machine including, a work support, a pair of laterallyspaced clamping members arranged to engage the work on the respectivesides of a weld to be effected, pressure actuated means carried by thesupport for moving said clamping members into and out of clampingposition, a track carried above the work support, a carriage mounted formovement along the track, electrodes on the carriage arranged to engagethe work, percussion means on the carriage and operable on the workintermediate said electrodes, means for moving the car riage along thetrack, means for rendering said moving means effective, means supplyinga welding current to the electrodes, a switch controlling said currentsupply, and means for opening said switch at selected predeterminedlimits of movement of the carriage.

9. A welding machine including, a work support, a pair of laterallyspaced clamping members arranged to engage the work on the respectivesides of a weld to be effected, means carried by the support for movingsaid clamping members into and out of clamping position, a track membercarried above the Work support, a carriage mounted for movement alongthe track member, electrodes on the carriage arranged to engage thework, percussion means on the carriage intermediate the electrodes andoperable on the work in the path of the current passed between saidelectrodes, means for moving the carriage along the track member, meanson the carriage supplying a welding current to the electrodes, and meansfor raising and lowering the track member with respect to the support.

10. A welding machine including, a table-like work support, a beammember adjustably mounted above the table-like support, a carriagemounted for reciprocation on the beam member, a shaft having endsjournalled on the beam member and having threaded connection with saidcarriage, means for rotating the shaft to effect movement of thecarriage, welding means on the carriage including electrode wheelsarranged to engage work sheets carried on the table-like work support,percussion means on the carriage intermediate the electrode wheels,means for raising and lowering the beam member relative to the table,-like work support, and means on the beam member adapted to be engaged bythe carriage for stopping rotation of said shaft.

11. A welding machine including, a table-like work support, supportingmembers at opposite ends of the table-like work support, guides on saidsupporting members, a beam member having movable support on said guides,cams carried by said supporting members and arranged to engage said beammember, actuating means for the cams, a carriage mounted forreciprocation on the beam member, a shaft having ends journalled on thebeam member and having threaded connection with said carriage, means forrotating the shaft to effect movement of the carriage, welding means onthe carriage including electrode wheels arranged to engage work sheetscarried on the table-like work support, and percussion means on thecarriage intermediate the electrode wheels.

12. A welding machine including, a work support, laterally spacedclamping members arranged to engage the work on the respective sides ofa weld to be effected, pressure actuated means carried by the supportfor moving said clamping members into and out of clamping position, atrack extending parallel with the weld to be effected, a carriagemounted for movement along the track, electrodes on the carriagearranged to engage the work, percussion means on the carriage andoperable on the work intermediate said electrodes, means for moving thecarriage along the track, means for rendering said moving meanseffective, means supplying a welding current to the electrodes, a switchcontrolling said current supply, and means for opening said switch afterselected predetermined limited movement of the carriage.

13. A welding machine including, a work support, a transformer, acarriage supporting the transformer for movement across the worksupport, means for moving the carriage, a pair of spaced electrodewheels having electrical connection with the transformer, and meansseparately and movably mounting the electrode wheels on the transformerfor movement to and from the work support independently of thetransformer.

14. A welding machine including, a work support, a transformer, acarriage supporting the transformer for movement across the worksupport, a pair of spaced electrode wheels having electrical connectionwith the transformer, means pivotally mounting the electrode wheels onthe transformer, and means for moving the electrode wheels on saidpivotal means for raising and lowering the wheels to and from the worksupport.

15. A welding machine including, a work support, a transformer, acarriage supporting the transformer for movement across the worksupport, a. pair of spaced electrode wheels having electrical connectionwith the transformer, means pivotally mounting the electrode wheels onthe transformer, and fluid pressure means for yieldingly retaining thewheels in welding contact with work carried by the work support.

HARRY A. ALLSHOUSE. REX H. DYER.

